Insulating the 2nd Floor

[99Mike]

I recently had built a 2 story detached stick built garage in North Carolina. I am in zone 3. The downstairs is insulated with R15 in the walls and R38 in the downstairs ceiling/upstairs floor. The garage door is also insulated and I installed a mini split for the downstairs. The upstairs room is 12 X 27 and I'd like to insulate it to make it more usable and welcome suggestions on how to do it. The room will never be a living space, but primarily used for storage. The roof trusses are 2 X 6. There is a ridge vent and soffits for ventilation. I may put a window A/C unit in for use in the hotter months. The second picture is the downstairs insulation. Ideas?

 

[twistedstang]

I'm getting ready to do the same to mine. What I worry about is it being sealed up tight with no hvac. Once my lower level was finished I noticed mold starting on my floors, boxes, car interiors, etc from not having dehumidification.

 

[billconner]

I'm assuming attic trusses? I haven't done it but when I think about insulating a room in attic trusses, I'm a little stymied. Too little depth in or real near sloped section for much insulation and venting.

Jumping to the end, hot roof with open cell foam full depth of top chord of trusses, from attic floor to ridge. Don't bother insulating knee walls, just lots of leaky gaps.

(I guess you'd might be more sure to avoid any moisture problems with 2" of closed cell and the rest open, but seems fussy. All closed cell also fine - just more expensive. Most important - a top notch installer.)